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FIR filtering a limited subband of a signal

I have a full band audio signal (sampled at 48000Hz) and I want to process only the low frequencies with an FIR filter. The maximum frequency that I need to process with the FIR is 3000Hz, i.e., an ...
Florent's user avatar
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1 vote
0 answers
100 views

In "Mel spectrogram" or "Mel filterbanks", what does Mel mean and why is it often capitalized? [closed]

In "Mel spectrogram" or "Mel filterbanks", what does Mel mean and why is it capitalized ? It doesn't seem to be the name of a person.
f10w's user avatar
  • 111
2 votes
1 answer
61 views

2x oversampling channelizers and perfect reconstruction

For perfect reconstruction, it seems that $2\times$ oversampling allows a prototype filter that ensure the spectrums of the subchannels overlap correctly. In the gnuradio reference on this it seems ...
John McGrath's user avatar
2 votes
1 answer
78 views

Comparing results for spectrum generating in matlab using STFT and Filterbank approach

To analyse data in the frequency domain I often use functions like stft() in Matlab. Inspired by this video and this article I have compared the results of ...
Matthias La's user avatar
0 votes
0 answers
81 views

High Resolution Spectral Analysis

Inspired by this post and this video I have been playing around with different methods in Matlab to do spectral analysis. In the past I have simpy used digital fourier transforms and played around ...
Matthias La's user avatar
1 vote
0 answers
66 views

Why filter-bank energies coefficients are same through the frame?

I am trying to implement MFCC's from scratch in C++. In each frame, I am processing real-valued data to construct MFCC vectors. Although I think that my implementation is correct, the testing result ...
Yalçın Cenik's user avatar
1 vote
1 answer
153 views

Spectrum analyzer with multirate filter bank

This paper gives a spectrum analyzer using the multirate filter bank technique. The basic idea of the paper is that STFT can be interpretated as a uniform DFT filter bank. But the baseband filter of ...
ecook's user avatar
  • 379
0 votes
1 answer
43 views

jsfx filter bank frequency response issue

I am probably going about this completely wrong, but I'm trying to implement a filter bank in reaper's JSFX as follows: First, split the spectrum into half (via aritmetic and a fo-lpf), then split ...
micsthepick's user avatar
1 vote
1 answer
90 views

What will happen when we reverse an analysis/synthesis system?

Suppose that we have four filters $H_0(z), H_1(z), F_0(z),$ and $F_1(z)$ forming a classic perfect-reconstruction 2-channel filter bank: Will the perfect reconstruction still be achieved if we ...
WilliamW's user avatar
2 votes
2 answers
405 views

DFT filter bank interpretation, and perfect reconstruction?

I think I understand how the DFT can be seen as a bank of bandpass filters. I am trying to understand the IDFT within the same framework. I understand that the IDFT can be seen as summing linear ...
B.Ogles's user avatar
  • 23
0 votes
0 answers
59 views

extract analysis and synthesis weighting filters

For regular FIR filters we can feed an impulse signal to get the coefficients, but how about filterbanks? Let's say I have a uniformly modulated filterbank with hop size H and FFT size M, implemented ...
Ali's user avatar
  • 153
3 votes
2 answers
2k views

Can anyone explain how dft works as a filter bank?

When we take the fft of input signal, the fft formulas say us to down convert the 2pik/N frequency content of input signal and sum one period interval. This gives us a just one complex number,not an ...
Ahmet Serdar's user avatar
1 vote
2 answers
214 views

Quadrature Mirror Filter symmetry? How to understand this notation

The QMF symmetry of a two-channel filter bank is given by $H_1(z) = H_0(-z)$ I don't understand why such a constraint is quadrature and mirror symmetry. Are $H_1$ and $H_0$ quadrature and mirror ...
ecook's user avatar
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1 vote
0 answers
164 views

Strong vs weak COLA (constant overlap-add)

My question is on the aliasing cancellation of the OLA method when spectral modification is involved. The book related to this question is given by this link. As stated by the webpage, for weak COLA ...
ecook's user avatar
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1 vote
0 answers
60 views

Relation between DFT filter bank and sliding DFT

I am reading the book 'spectral audio signal processing'. It says when $n=LN-1$ for any integer $L$, the sliding DFT $$X_n(k)=\sum_{m=0}^{N-1}x(n+m)e^{-j2\pi mk/N}$$ coincides with the DFT filter bank....
ecook's user avatar
  • 379
1 vote
1 answer
128 views

Building the low pass filter in the wavelet scattering transform

In 1, analyzing the equivalence between MFCC and wavelet transform, the scaled wavelets are truncated for $\lambda < 2\pi Q/T$ to fit the time spread of the wavelets within the length $T$ of the ...
dac's user avatar
  • 77
2 votes
3 answers
3k views

Polyphase filter bank channelizer FFT or IFFT

I am referring to the Xilinx application note Polyphase Filter Bank Channelizer. The receiver portion should have FFT but the pdf mentions IFFT in both Tx and Rx. The paper by F. J. Harris, C. Dick ...
Swapnil Bhole's user avatar
1 vote
0 answers
47 views

Get Spectrogram from Filtered Power Spectrum

My objective is to get the higher resolution of spectrogram on the high-frequency area (2000 Hz - 5000 Hz) for a section of speech audio. I know that we typically apply Mel-scaled filter bank to get ...
John's user avatar
  • 11
0 votes
0 answers
77 views

Filter Bank and Auto-Encoder

I'm trying to find an intuition behind auto-encoder using an analogy with filter banks. I can comprehend the encoder and analysis filters in a filter bank as extracting features from the input signal ...
tushar's user avatar
  • 101
0 votes
1 answer
166 views

Perfect reconstruction in two-channel filter bank

[from Discrete-time Signal Processing by Oppenheim and Schafer, 3rd ed.] I was not able to prove this: If the analysis and synthesis filters are ideal so that they exactly split the band 0 ≤ |ω| ≤ π ...
DSPinfinity's user avatar
0 votes
1 answer
1k views

what is OQAM (Offset QAM) and why it is required?

Currently I am studying about a modulation technique FBMC (Filter Bank Multicarrier) which is a predecessor of OFDM. The difference with OFDM is that, FBMC does not have a CP (Cyclic Prefix) which is ...
SAM's user avatar
  • 15
0 votes
0 answers
1k views

Using FFT for implementing a filter bank

I am trying to use Fast Fourier Transform (FFT) for decomposing an audio signal into 8 sub-bands according to this link but the problem is the frequency response of the result contains only the first ...
reza's user avatar
  • 51
0 votes
3 answers
1k views

How and why does downsampling reduces resolution in time

in my Course we talked about filter banks and the prof said that we get reduced resolution in time because of the downsampling after the band-pass filters. Is this because we now have fewer sample ...
SignalQuestions's user avatar
1 vote
2 answers
603 views

filterbank: understand the different responses at the center frequency of each filter

I'm computing filterbank by applying 26 triangular filters on a Mel-scale to the power spectrum of an audio frame to extract frequency bands, and I found that some references use filterbank with equal ...
Abdulkader's user avatar
0 votes
1 answer
114 views

Wavelets: Reconstruction Filters for 2 Level Decomposition

I am trying to understand the reconstruction part after discrete wavelet decomposition and how do we get approximations and details at various levels. Most textbooks show the complete reconstruction ...
ACR's user avatar
  • 561
1 vote
2 answers
614 views

Advantages of an orthogonal filterbank

What are the advantages orthogonal filterbanks such as the DFT or DCT have over non-orthogonal filterbanks? I have heard quite often that they have attributes that are desirable when modifying the ...
Nils Werner's user avatar
0 votes
0 answers
228 views

Understanding the magnitude of frequency response filterbank based on elliptic filters

I've implemented a 10-channels filterbank with octave-scaled second-order elliptic filters using the Python's library scipy.signal. Here is the magnitude of the frequency response: Can someone ...
enne's user avatar
  • 1
1 vote
0 answers
95 views

Why do additional harmonics arise after the filter bank?

I'm trying to implement direct implementation of MDCT filter bank. So, some additional artefacts have appeared after all of the routines. The spectrum of the initial signal looks like: ...
vovenur's user avatar
  • 11
1 vote
1 answer
1k views

Discrete Wavelet Transform (DWT) Filter Bank

I have some stumbling block in my thesis writing. Do we use the same filter pair while implementing DWT filter bank with downsampling of the filter output, or filters do change also from level to ...
Андрей Виноградов's user avatar
0 votes
0 answers
36 views

Equal power filterbank

Is there a specific algorithm/formula for computing the bandwidths of filter banks across a frequency range where each bank has equal power/volume/intensity? (The bandwidths will be different for ...
Flarp's user avatar
  • 1
1 vote
2 answers
1k views

Polyphase Analysis Filter Bank

I have a question regarding the polyphase DFT filter bank implementation in this page. (https://cnx.org/contents/Peqc-TK2@16/Uniformally-Modulated-DFT-Filterbank) In figure 2, to analyze the kth ...
Narendra Deconda's user avatar
1 vote
0 answers
137 views

Discrete Wavelet Transform: Specifics of Filter Bank

So I have been given to understand that the discrete wavelet transform is able to provide both time and frequency resolution in ways that classic Fourier and even short time Fourier cannot. By ...
Jack Frye's user avatar
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0 votes
1 answer
82 views

How are 12 outputs being reconciled so that a Homomorphic filter could be applied?

Take a look at this paper. It writes in the section 4.1: We selected 12 not overlapping filters, to analyze 12 different directions, rotated with respect to 15° each other. A homomorphic filter is ...
user avatar
3 votes
2 answers
2k views

What is a filter bank?

Suppose, I have 3 kernels: $$ \left[ \begin{array}{cc} a&b&c\\ d&e&f\\ g&h&i \end{array} \right] $$ $$ \left[ \begin{array}{cc} p&q&r\\ s&t&u\\ v&...
user avatar
0 votes
0 answers
303 views

How does this Odd stacking DFT work?

I have just read on page 3 of this paper: https://www.onsemi.com/site/pdf/Filtering_Hearing_Ai.pdf That an "odd stacking" DFT can be created, essentially sacrificing the DC and Nyquist bands to ...
kippertoffee's user avatar
-1 votes
1 answer
67 views

Speech Processing applications: stereo data for features

I am working on speech databases that have a stereo format. I want to extract spectral information (Mel-filterbanks, MFCC, LPCC) and also some other prosody features like the fundamental Frequency F0. ...
Rachid Riad's user avatar
-1 votes
1 answer
205 views

Wavelets and bank filters

The wavelet transform has a problem as it gives poor time resolution for low frequencies and poor frequency resolution for high frequencies according to uncertainty conditions. This appears well ...
EWF's user avatar
  • 9
2 votes
0 answers
156 views

Perfect reconstruction of 2 channel filter bank

I am studying Perfect reconstruction of 2 channel filter bank for using Biorthogonal Spline wavelet for decomposing ECG signal. I am using Wavelets and Filter Banks By Gilbert Strang, Truong Nguyen to ...
Waqar Ahmed's user avatar
1 vote
1 answer
258 views

Filter bank for complex spectrum

I'm using a complex-valued baseband signal as my input for subband adaptive filtering. Therefore i have a complex input spectrum. My problem is now, how to split my complex spectrum into $N$ equally ...
Don's user avatar
  • 165
2 votes
1 answer
572 views

Norm MPEG-1 Layer III (Mp3) Filter banks distortion

So, I'm working with the filter banks used in Mp3, in Matlab. I am obtaining quite a huge distortion in the output and I don't really know whether I'm making something wrong. I've reviewed the ...
f.gallardo's user avatar
1 vote
0 answers
292 views

Converting a parallel filterbank to cascade structure

I have a bank of 12 bandpass filters (biquads) that I use for spectral modelling. Each filter is centered around a specific "mode" frequency, and has its own resonance. Until now I have implemeted ...
Florent's user avatar
  • 754
2 votes
2 answers
164 views

Sub-band partitioning of filter-banks

In ECE-700 Filterbank Notes the partitioning is $ \Delta = \frac{2\pi}{M}$ with center-frequencies at $ \omega_k = \frac{2\pi}{M}k$ which makes me wonder, considering that frequencies in the range ...
Starhowl's user avatar
  • 379
4 votes
3 answers
4k views

What is the relation between windowing and hopping in audio DSP

While using short-time Fourier transform (STFT), it is common to use window function, usually tapered. Will this not alter the original signal $x[n]$ and the STFT may no more be the true STFT of $x[...
Aravinda Murthy's user avatar
1 vote
0 answers
289 views

What is advantage of Logarithmic Sampling?

Logarithmic Fourier Transformation This paper starts off in the abstract saying that the given audio signal is sampled logarithmically. We also know that the human ear has a sort of a filter bank ...
Viswanath Hariharan's user avatar
1 vote
0 answers
282 views

What is logarithmic mapping in a filter bank such as the one in the human ear?

"The spacing of the filters in a filter bank used to make an ordinary spectrogram is linear, whereas an auditory filter bank has a spacing that corresponds to the way in which sinusoidal frequency ...
Viswanath Hariharan's user avatar
2 votes
1 answer
55 views

Sub-band factor 0.5 in uniform filterbank

Is there someone who knows where the factor $\frac{1}{2}$ in front of $U_i(z)$ comes from?
Starhowl's user avatar
  • 379
1 vote
1 answer
47 views

Should I (and if yes, how can I) assure channel-dependant temporal accuracy in a filterbank?

Imagine a filterbank with N channels. A possible implementation is a sliding short-time FFT. If you want to capture frequencies as low as 100 Hz, the length of your sliding window should be at least ...
BNJMNDDNN's user avatar
  • 225
7 votes
2 answers
330 views

Is this signal perfect reconstructable?

The question is as follow: Let me do the analysis: The downroad first: \begin{align} X_1(z) &= z^{-1}X(z)\\ X_2(z) &= \frac{1}{2}\left\{X_1\left(z^\frac{1}{2}\right)+X_1\left(-z^\frac{1}{2}\...
stander Qiu's user avatar
8 votes
3 answers
3k views

MP3 Filterbank + MDCT: Why?

What is the rationale for the two-step process the MP3 format performs, first decomposing the input into 32 subbands of 6/18 samples each then performing MDCT on each subband individually? Why not ...
Justin Olbrantz's user avatar
1 vote
2 answers
1k views

How to reverse Mel scale

The conventional MEL scale converts the frequency scale using the following formula: $$M_f = 1127.01048 \cdot \log\left(\frac{f}{700} +1\right)$$ I want to use a reverse scale where resolution is ...
Astro's user avatar
  • 113